Abrasive wheels



Dec. 20, 1966 J. L. HENSLEY ABRASIVE WHEELS 2 Sheets$heet 1 OriginalFiled Dec. 6, 1961 INVENTOR JAMES 4 #506415 y ATTORNEY;

Dec. 20, 1966 HENSLEY 3,292,311

ABRASIVE WHEELS Original Filed Dec. 6, 1961 2 Sheets-Sheet 2 F [g 6INVENTCR.

James L, #015 I0 ATTORNEYS United States Patent f 3,292,311 ABRASIVEWHEELS James J. Hensley, Clinton, Tenn. '(P.0. Box 1269, Knoxville,Tenn.) Original application Dec. 6, 1961, Ser. No. 157,514, now PatentNo. 3,255,289, dated June 7, 1966. Divided and this application Oct. 16,1964, Ser. No. 404,267 2 Claims. (Cl. 51-206) This application is adivision of my prior application for Methods of Making Abrasive Wheels,Serial No. 157,514, filed December 6, 1961, now Patent No. 3,255,289.

This invention relates to improvements in abrasive wheels, particularlyof the character used for cut-oft machines.

One method of manufacturing abrasive wheels involves the use of acircular type press. The desired quantity of abrasive material is formedinto the mold and spread over the area thereof. This material usually ismade of abrasive particles combined with a binder capable of beingpressed and hardened to form a disc. Frequently, such a disc may be madeup to thirty-four inches in diameter and seven thirty-seconds inchthick. A top mating pressure plate is used to press the material to thedesired shape and density.

Thereafter, the wheel thus formed is removed from the press for curing.It must be kept flat until fully cured and ready for use. If laidwithout support over the entire area thereof, the wheel is subject towarping, taking a permanent set out of flatness, which would destroy itsusefulness.

In the use of an abrasive wheel, especially of large diameter size, andin making deep cuts, the wheel is subject to many adverse operatingstresses, such as excessive side binding which required increased powerto continue the operation thereof. Moreover, cooling of the wheelbecomes difficult in making deep cuts.

It has long been known that the wheel would be improved by making therim section thicker than the web section inwardly of the rim, but nosatisfactory way has been found heretofore of making the wheel with athicker rim and maintaining it in condition for use. An attempt has beenmade to shape the press to form a uniform taper in the web sectioncontinuously from the peripheral edge of the rim to the center. Thisleft a feather edge that was not sufiicient to prevent side travel.Moreover, it required a pallet having a supporting surface complementaryto the surface of the wheel to support the latter to prevent distortionto one flat side during curing and continuously until put intosubstantial use.

One object of this invention is to overcome the objections to abrasivewheels with straight sides and to improve the method of making abrasivewheels.

Another object of the invention is to provide in the method ofmanufacturing an abrasive wheel with a thickened rim, of support meanstherefor Within the face of the Wheel and readily removable when thewheel is ready to be put to use.

Still another object of the invention is to provide for molding anabrasive wheel upon a separate core placed within the mold and ofappreciably smaller area than the area of the mold and wheel and moldedin the surface of the wheel to be removed from the mold therewith butcapable of ready separation from the wheel when the latter is to beused.

These objects may be accomplished by placing one or more sheets ofmaterial in the bottom of the mold and of appreciably less area than thearea of the mold, and also of appreciable composite thickness so as toform a Web section of less thickness than the thickness of the PatentedDec. 20, 1966 rim section. The material used in the mold can be ofvarying or any desired thickness according to the amount of steppedtaper desired in the finished wheel. A like number. of sheets ofmaterial preferably are used under the pressure plate on top of thecomposition for a properly balanced wheel. These sheets would adhere tothe formed wheel and remain thereon after removal from the mold andduring curing, and, in fact, until the wheel is ready for use.

This method is illustrated in the accompanying drawings, in which:

FIG. 1 is a cross section through a mold showing layers of moldingmaterial to be applied to opposite sides of an abrasive wheel in themolding thereof;

FIG. 2 is a cross section through the molded wheel after removal fromthe mold;

FIG. 3 is a similar view of the wheel ready for use;

FIG. 4 is a cross section of the wheel in the work;

FIG. 5 is a plan view of a modified form of wheel;

FIG. 6 is a detail perspective view of the modified abrasive wheel madewith molding sheets of material of the character illustrated in FIG. 5;and

FIG. 7 is a sectional view of the modified abrasive wheel in the work.

The relative sizes and dimensions of parts are exaggerated in thedrawings for clearness of illustration.

The invention is illustrated in connection with a mold of conventionalform for clarity of illustration. This mold comprises top and bottomplatens 1 and 2 shaped to mold a mass of abrasive plastic material toform a wheel of the desired contour and size.

The bottom platen 2 is provided with a cylindrical cavity 3 having abottom face 4 usually smooth and flat. The under surface 5 of the topplaten 1 is also usually flat and smooth continuously throughout thearea of the top platen 1.

The means for forming the center hole in the wheel is illustrated as apin 6 rising from the bottom cavity face 4 and of a length to extendentirely through the mold cavity. Any suitable means may be used for thepurpose.

In making a wheel according to this invention, the moldable abrasivematerial is placed in the mold cavity 3 of a quantity according to thesize and thickness of the wheel to be made, after which the top platen 1may be applied thereto to effect the molding operation in the usual way.Suitable pressure is applied to the top platen and held for a length oftime suflicient to effect the molding operation. Lining sheets a and bare shown in FIG. 1 extending over and throughout the respective areasof the surfaces 4 and 5 to facilitate separation of the molded wheelthereform. These lining sheets may be used if desired, but are notrequired according to this invention.

The abrasive wheel is illustrated in FIGS. 2 to 4, made with a thick rimsection R and a relatively thinner web section W. This relativelythinner web section W is formed by one or more molding sheets on eitheror both sides of the mold cavity. In the example illustrated, suchmolding sheets are shown at c, d and e stacked fiatwise on the bottomface 4 of the cavity 3, and also three such molding sheets are shown atf, g and h stacked against the bottom face 5 of the top platen or thelining sheet b, if used.

Each of the molding sheets 0 to h extends symmetrically of the moldcavity but has its periphery spaced inwardly an appreciable distancefrom the periphery of the cavity. The largest diameter sheet or sheetsthereof are in the inner periphery of the rim R. Where several sheetsare used in each stack these form shoulders S on the face or faces ofthe wheel in one or more steps between the rim R and the web W of thewheel.

The molding sheets ch may be held in place in any suitable manner in themold cavity and on the ,undersurface of the top platen 1. The sheet orsheets in the bottom of the cavity may be provided with central openingsto fit around and on the central pin 6. In like manner, the sheet orsheets that are secured to the undersurface of the top platen 1 may beheld in place around the opening in the bottom face of that platen inwhich the pin 6 is received when the platen is inserted in the cavity.Suitable means should be provided on the top platen to hold the sheetsthereto, but to allow ready separation therefrom when the top platen isremoved from the mold.

The molding sheets c-h may be formed of any suitable material founddesirable for the purpose, such, for example, as Kraft paper, wax paper,or aluminum foil. The material should be such as would enable the sheetor sheets to be peeled readily from the formed abrasive disc or wheelwhen the latter is to be put into service. The molding sheet, if one isused on each surface, or the composite sheets if more than one are usedon each surface, should heof suificient thickness so as to separate theweb section W from the rim section R and to provide a definitely thickerrim section than the web section, as somewhat exaggerated in FIGS. 3 and4. The greater thickness, nevertheless, of the rim section should besuch as will provide a radial addition to the rim of uniform thicknessso as to provide definite support for the wheel in the kerf formed inthe material to prevent side travel of the wheel in operation. At thesame time, the spacing of the web portion from the sides of the formedkerf permits free access of the cooling liquid to the rim andsubstantially throughout the area of the wheel to obtain maximum coolingeffect.

After molding the wheel with the molding sheets embedded therein, theWheel is removed from the mold and cured in the usual manner. Themolding sheets remain in place on the wheel until the latter is readyfor use. Then they may be peeled ofi? or separated, so as to provide forthe operation of the wheel in the usual manner. When in place on thewheel, the molding sheets provide uniform support for the wheel, bothduring curing and during handling or storage.

Usually, these molded abrasive wheels are supported flat and theyrequire support continuously throughout the area of each to prevent thepossibility of distortional warpage. By molding the sheets directly inthe surface of each wheel, the sheets remain in the wheel embeddedtherein and support the surface uniformly throughout.

Moreover, the provision of molding sheets in the center A portion of thewheel, spaced inwardly from the surrounding rim section, provides forgreater pressure being applied to this center section, which willcompact the moldable abrasive material with greater density than in therim section. Thus, the wheel will harden more effectively in the centerand produce a more durable wheel than one of uniform density throughout.

It is also possible to use molding sheets to modify the surface of theabrasive wheel in other respects than has been illustrated in FIGS. 1 to4. One such sheet'would be used in the bottom of the cavity and anotherpreferably in the top thereof under the top platen. When the abrasivematerial is thus deposited in the cavity between the sheets, a wheelwould be molded in the usual manner, as indicated at W in FIG. 6. Such awheel would have alternate ribs and grooves extending radially thereofon one or both opposite faces of the wheel, which would have excellentcutting and cooling eflFect and would minimize side binding during theoperation of the wheel, as will be apparent from FIG. 7.

The alternate grooves and ribs will provide courses W2 for the coolingliquid to flow radially outward along the wheel entirely to theperiphery thereof from the center portion W3 thereof during theoperationof the cutting of metal, stone or other materials. In otherrespects the method of use and of manufacture illustrated in FIGS. 5 to7 would be the same as set forth above and involve the use of similarmaterials.

While the invention has been illustrated and described in certainembodiments, it is recognized that variations and changes may be madetherein without departing from the invention set forth in the claims.

I claim:

1. An abrasive wheel comprising a plastic body having abrasive particlesembedded therein, said body having a thicker peripheral portion and arelatively thinner inter- 1 mediate web portion forming recesses atopposite sides of the body each having stepped portions progressivelydecreasing in area from the outer to the inner sides thereof, aplurality of sheets of material extending throughout the respectiverecesses and with the sheets respectively decreasing in area from theouter to the inner sides of the respective recesses, and means forattaching the sheets to the web portion for handling and for peeling ofthe sheets therefrom when the wheel is to be put into service.

2. An abrasive wheel comprising a plastic body having abrasive particlesembedded therein, said body having a thicker peripheral portion and arelatively thinner intermediate web portion forrning recesses atopposite sides of the body, a plurality of sheets of material extendingthroughout the respective recesses and with the outer faces of theplurality of sheets co-planar with the outer. faces of the thickerperipheral portion, and means for attaching the sheets to the webportion for handling and for peeling of the sheets therefrom when thewheel is to be put into service. I

References Cited by the Examiner UNITED STATES PATENTS 2,259,554 10/1941Clark 51-168 FOREIGN PATENTS 194,274 1/1958' Austria. ROBERT C. RIORDON,Primary Examiner.

L. S. SELMAN, Assistant Examiner.

2. AN ABRASIVE WHEEL COMPRISING A PLASTIC BODY HAVING ABRASIVE PARTICLESEMBEDDED THEREIN, SAID BODY HAVING A THICKER PERIPHERAL PORTION AND ARELATIVELY THINNER INTERMEDIATE WEB PORTION FORMING RECESSES AT OPPOSITESIDES OF THE BODY, A PLURALITY OF SHEETS OF MATERIAL EXTENDINGTHROUGHOUT THE RESPECTIVE RECESSES AND WITH THE OUTER FACES OF THEPLURALITY OF SHEETS CO-PLANAR WITH THE OUTER FACES OF THE THICKERPERIPHERAL PORTION, AND MEANS FOR ATTACHING THE SHEETS TO THE WEBPORTION FOR HANDLING AND FOR PEELING OF THE SHEETS THEREFROM WHEN THEWHEEL IS TO BE PUT INTO SERVICE.